THE Servant of all time. Often imitated, but never duplicated. Ever since the original Fate/Stay Night release all the way back in 2004, Saber has made her mark on fans of Fate, Visual Novels, and Animanga worldwide and remains the series mascot to this day, spawning a deluge of clones - both in universe and out and both figuratively and literally - it seems that despite all this, there's no Servant quite like Saber. Something about this one very, very hungry British (Welsh? Cornish? Whatever you call someone from Dover? IDK) Knight has endeared her in the eyes of almost all who've so much as glampsed at her? Is it because of her dedication to her ideals and her nation? Her nobility? The deep meaning of the character or just because she looks cute?
To be honest, Saber is such an icon that it's difficult really to describe her as anything but Saber - she's kind of like Superman or Goku in that way.
This page serves a character shrine for our great King of Knights.
Depending on if you count Arthur, or Proto-Saber, who is a different person based off the same mythological source and created by Nasu, as the same person as Saber proper, she holds the honour, alongside Ayaka Sajyou, Proto-Cu, Proto-Gilgamesh, and the other Fate/Skipper characters as being one of Nasu's first created characters, even predating the Mahoyo cast.
If we claim that too much was changed between Arthur and Artoria for them to count as the same character, then she becomes about 7-8 years younger than Aoko and co depending on when development for Fate/Stay Night proper began.
This makes her a sort of Schrödinger's old woman, like this image:
She would be, as of the writing of this in 2025 either 35 (going of the writing of Fate Skipper in 1990) or 21 (going off the 2004 release of Fate/Stay Night).
...So not actualy all that different in terms of age.
As the story goes, Nasu wrote a book about various heroes fighting each for the Holy Grail called 'Fate Skipper' because he liked Samurai Resurrection and wanted to do something similar but with heroes around the world instead of just Japan. He chose King Arthur as one of them, no idea why, but considering Saber would have been one of the MCs, maybe Nasu is really into British mythology. He started this in 1990 but only got about as far as Saber vs Kojiro - so I'm assuming the stuff that takes place later (based on when the events occur in relation to each other in Fate/Stay Night) like Saber being corrupted and Ayaka and Lancer having to team up against him and Gilgamesh showing up - and Manaka's likely appearance as the final boss was only drafted down and not fully written.
That or Kojiro was going to be the final boss. Maybe that's where Saber dueling Kojiro at the end of UBW came from.
Some day later I'd like to (once I've read the Silver Sky books) figure out what in Fate/Prototype is changed or rearranged from Fate Skipper and try and see what DNA of Fate Skipper characters and events remains in those of Fate/Stay Night - like Illya likely being based off Manaka and The Shirou/Rin/Lancer team-up while Saber is kidnapped by Caster likely coming from the Lancer/Ayaka team up to deal with Sancraid's Berserker and corrupted Saber. I wonder if Gilgamesh killed Sancraid like Archer does Caster immediately after that, because he apparently also beats Berserker.
Proto/Skipper Saber was apparenly the ideal hero for the 1990s. English language pop-culture got all grim back then (as it seems alternate between optimisitic and pessmistic every 10 years) but I have no idea if that also applies to Japan's. They had an economic collapse, and I'd be pretty down in the dumps if that happened to me. Nasu claimed that Archer inherited his nihilistic statements but also mentions him being mature with a sense of justice and 'a pleasant hero', so maybe he was sort of a cross between a Superman type paragon and Archer in terms of personality? He looks quite grim in the Character Material art but those might just be drawings of him during emotional moments or something.
Proper-Saber seems to have inerhetied the 'calm' they mentioned as well as his goals and sense of chivalry, but I wouldn't call the stoic and often emotionless-seeming Saber of the first couple of nights of Fate/Stay Night a 'pleasant hero'. Its possible he was originally more approachable than Saber ended up being.
There's always the actual appearences of Proto-Saber to gain insight into his original personality, but in the years between the drafting of Fate Skipper and the Prototype characters' first appearence in Carnival Phantasm, its possible that like how Theseus was swapped out for Perseus, that proto-Saber's personality changed.
As one last piece of trivia for Proto-Saber, for some reason, his class is written (in English) as 'Archetype Saver' - Buddha's class in Extra in character material. Considering the Beast with 7 heads is the Aŋra Mainiiu of Fate/Prototype, it's possible he was going to reclass to a more "holy" Servant type to take him down.
Or, like Altria, it's a misromanisation.
Regardless, after the success of Tsukihime, Type Moon decided to bring back Fate Skipper, one name and gender change later, we get Fate/Stay Night.